DEEP: Nitrogen Control Program for Long Island Sound

Nitrogen Control Program for Long Island Sound

Each summer, the bottom waters in the western half of Long Island Sound experience hypoxia, or very low levels of dissolved oxygen. Extensive monitoring and modeling of Long Island Sound have identified the excessive discharge of nitrogen from human activities as the primary pollutant causing hypoxia. Nitrogen fuels the growth of algae in the Sound, which eventually decays, consuming oxygen in the process. There is enough nitrogen added by human activity to cause a hypoxia problem each summer. 

In 2001, Connecticut DEEP and New York DEC, in concert with US EPA, completed plans for nitrogen control that identifies the maximum amount, or the Total Maximum Daily Load (TMDL), of nitrogen that can be discharged to Long Island Sound without significantly impairing the health of the Sound.  One of DEEP’s management strategies to reduce nitrogen loading was to develop an innovative nitrogen-trading program among 79 sewage treatment plants located throughout the state. Through the Nitrogen Credit Exchange, established in 2002, Connecticut has reduced the nitrogen load from that source by nearly 65% by 2014.

On January 2, 2002, pursuant to Public Act 01-180, the Department issued the General Permit for Nitrogen Discharges (also known as the Nitrogen General Permit). The permit was effective on January 1, 2010 and will expire on December 31, 2015.

On June 5, 2015, Public Act 15-38, an act concerning the sustainability of the Nitrogen Credit Exchange Program was signed by the Governor. 

The renewal of the General Permit for Nitrogen Discharges proposes that Publically Owned Treatment Works (POTW's) continue with the same permit limits as listed in the current General Permit for the year 2014. These facilities, in aggregate, must continue to achieve a reduction in the annual loading of total nitrogen to Long Island Sound by approximately 64% from the original baseline TMDL in order to continue to meet the target 2014 waste load allocation. No changes are proposed to the General Permit for Nitrogen Discharges except for some minor technical revisions.

General Permit for Nitrogen Discharges (NEW - June 2015)

  • Nitrogen General Permit - Regulates the discharge of total nitrogen from 79 Publicly Owned Treatment Works (POTW) in Connecticut. Effective January 1, 2010 and expires December 31, 2015

General Information on the Nitrogen Trading Program

Total Maximum Daily Load (TMDL) for Nitrogen

Reports of the Nitrogen Credit Advisory Board to the
Joint Standing Environmental Committee of the General Assembly
Nitrogen Credit Exchange
Connecticut’s Nitrogen Credit Exchange – An Incentive-based Water Quality Trading Program
For more information on:
Nitrogen Credit Exchange Program, please contact Iliana Raffa at (860) 424-3758
Baseline nitrogen loads, waste load allocation and permitting, please contact CT DEEP at (860) 424-3704



Content last updated: June 26, 2015